Fire retarding systems or ingredients for use in polymeric compositions and other organic combustible materials have for some years been primarily based upon combinations of halogen-containing compounds, such as chlorinated hydrocarbons, with antimony compounds, such as oxides or halides of antimony, for example, as disclosed in U.S. Pat. No. 2,480,298 of Aug. 30, 1949. However, there remains a need to both improve upon such conventional fire retarding systems, and also to eliminate halogens or compounds thereof and costly antimony compounds from many combustible materials or products without foregoing effective resistance to fire.
Moreover, loss of elasticity, or embrittlement, upon exposure to high temperatures has been a longstanding impediment of many common elastomers. The deteriorating effect of heat upon elastomers has prompted continuing efforts and the use of a variety of remedial measures to improve their resistance to heat, such as the development and use of antioxidants or agents which block the action of oxygen or free radical forming ingredients, and new compound formulations.
The characteristic loss of elasticity or embrittlement of elastomers is a particularly significant and critical problem in the electrical insulating field wherein conductors insulated with heat degradable elastomers are utilized in areas which are exposed to high temperatures, such as leads or wires in or about motors and transformers, or within apparatus containing heating elements or which are otherwise disposed in locations encountering high temperatures.